WASHINGTON (CNN) – Republican Sen. John Sununu, who trailed former New Hampshire Democratic Gov. Jeanne Shaheen by double digits in a hypothetical matchup at the beginning of summer, has now closed the gap to 5 percentage points, according to a new poll released Tuesday.

The American Research Group Poll was conducted over the weekend after Shaheen officially announced she would challenge Sununu for his seat in 2008. Shaheen and Sununu squared off in 2002 for the Senate seat.

In June, the ARG Poll showed Shaheen with a whopping 28 point lead over the first term senator. The new poll, conducted from September 14-17, has Shaheen up by 5 points just outside of the 4.2 percentage point margin of error. ARG surveyed 558 registered voters.

CNN posted an article just a few days ago of Ms Shaheen announcing her candidacy. The liberal posters were commenting how Ms Shaheen has already locked up the victory (more blue states, another victory for Dems, etc). I'm curious to hear the opinion of those over-confident dems explain how Mr Sununu has effectively closed a 28-point gap in a week?

This story exemplifies a common error made by the media. When comparing poll numbers for two candidates BOTH numbers have a margin of error. In this case Shaheen's 4.2 percentage point margin should be added to Sununu's 4.2 percentage point margin of error for a total margin of 8.4 percentage points. That means the 5 percentage point difference between the two is well WITHIN the margin of error, not outside the margin, as incorrectly reported by CNN. CNN should check with a statistician and then issue a correction.

As a citizen of New Hampshire, I will be one of those supporters that will definitely be voting for Shaheen. She was one helluva great governor and Sununu has turned a blind eye to those of us wanting him to put Bush in check. He has made some attempts to influence the war, but always voted with the leadership when he was told to. Party loyalty isn't what New Hampshire voters put him in office for. We put him there to be loyal to us back in his home state.